diff options
Diffstat (limited to 'gcc/bb-reorder.c')
| -rw-r--r-- | gcc/bb-reorder.c | 186 |
1 files changed, 166 insertions, 20 deletions
diff --git a/gcc/bb-reorder.c b/gcc/bb-reorder.c index 763cbe5..11423fe 100644 --- a/gcc/bb-reorder.c +++ b/gcc/bb-reorder.c @@ -87,6 +87,7 @@ #include "tree-pass.h" #include "df.h" #include "bb-reorder.h" +#include "except.h" /* The number of rounds. In most cases there will only be 4 rounds, but when partitioning hot and cold basic blocks into separate sections of @@ -1208,6 +1209,79 @@ get_uncond_jump_length (void) return length; } +/* Emit a barrier into the footer of BB. */ + +static void +emit_barrier_after_bb (basic_block bb) +{ + rtx barrier = emit_barrier_after (BB_END (bb)); + bb->il.rtl->footer = unlink_insn_chain (barrier, barrier); +} + +/* The landing pad OLD_LP, in block OLD_BB, has edges from both partitions. + Duplicate the landing pad and split the edges so that no EH edge + crosses partitions. */ + +static void +fix_up_crossing_landing_pad (eh_landing_pad old_lp, basic_block old_bb) +{ + eh_landing_pad new_lp; + basic_block new_bb, last_bb, post_bb; + rtx new_label, jump, post_label; + unsigned new_partition; + edge_iterator ei; + edge e; + + /* Generate the new landing-pad structure. */ + new_lp = gen_eh_landing_pad (old_lp->region); + new_lp->post_landing_pad = old_lp->post_landing_pad; + new_lp->landing_pad = gen_label_rtx (); + LABEL_PRESERVE_P (new_lp->landing_pad) = 1; + + /* Put appropriate instructions in new bb. */ + new_label = emit_label (new_lp->landing_pad); + + expand_dw2_landing_pad_for_region (old_lp->region); + + post_bb = BLOCK_FOR_INSN (old_lp->landing_pad); + post_bb = single_succ (post_bb); + post_label = block_label (post_bb); + jump = emit_jump_insn (gen_jump (post_label)); + JUMP_LABEL (jump) = post_label; + + /* Create new basic block to be dest for lp. */ + last_bb = EXIT_BLOCK_PTR->prev_bb; + new_bb = create_basic_block (new_label, jump, last_bb); + new_bb->aux = last_bb->aux; + last_bb->aux = new_bb; + + emit_barrier_after_bb (new_bb); + + make_edge (new_bb, post_bb, 0); + + /* Make sure new bb is in the other partition. */ + new_partition = BB_PARTITION (old_bb); + new_partition ^= BB_HOT_PARTITION | BB_COLD_PARTITION; + BB_SET_PARTITION (new_bb, new_partition); + + /* Fix up the edges. */ + for (ei = ei_start (old_bb->preds); (e = ei_safe_edge (ei)) != NULL; ) + if (BB_PARTITION (e->src) == new_partition) + { + rtx insn = BB_END (e->src); + rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); + + gcc_assert (note != NULL); + gcc_checking_assert (INTVAL (XEXP (note, 0)) == old_lp->index); + XEXP (note, 0) = GEN_INT (new_lp->index); + + /* Adjust the edge to the new destination. */ + redirect_edge_succ (e, new_bb); + } + else + ei_next (&ei); +} + /* Find the basic blocks that are rarely executed and need to be moved to a separate section of the .o file (to cut down on paging and improve cache locality). Return a vector of all edges that cross. */ @@ -1221,7 +1295,6 @@ find_rarely_executed_basic_blocks_and_crossing_edges (void) edge_iterator ei; /* Mark which partition (hot/cold) each basic block belongs in. */ - FOR_EACH_BB (bb) { if (probably_never_executed_bb_p (bb)) @@ -1230,32 +1303,71 @@ find_rarely_executed_basic_blocks_and_crossing_edges (void) BB_SET_PARTITION (bb, BB_HOT_PARTITION); } - /* Mark every edge that crosses between sections. */ - - FOR_EACH_BB (bb) - FOR_EACH_EDGE (e, ei, bb->succs) + /* The format of .gcc_except_table does not allow landing pads to + be in a different partition as the throw. Fix this by either + moving or duplicating the landing pads. */ + if (cfun->eh->lp_array) { - if (e->src != ENTRY_BLOCK_PTR - && e->dest != EXIT_BLOCK_PTR - && BB_PARTITION (e->src) != BB_PARTITION (e->dest)) + unsigned i; + eh_landing_pad lp; + + FOR_EACH_VEC_ELT (eh_landing_pad, cfun->eh->lp_array, i, lp) { - e->flags |= EDGE_CROSSING; - VEC_safe_push (edge, heap, crossing_edges, e); + bool all_same, all_diff; + + if (lp == NULL) + continue; + + all_same = all_diff = true; + bb = BLOCK_FOR_INSN (lp->landing_pad); + FOR_EACH_EDGE (e, ei, bb->preds) + { + gcc_assert (e->flags & EDGE_EH); + if (BB_PARTITION (bb) == BB_PARTITION (e->src)) + all_diff = false; + else + all_same = false; + } + + if (all_same) + ; + else if (all_diff) + { + int which = BB_PARTITION (bb); + which ^= BB_HOT_PARTITION | BB_COLD_PARTITION; + BB_SET_PARTITION (bb, which); + } + else + fix_up_crossing_landing_pad (lp, bb); } - else - e->flags &= ~EDGE_CROSSING; } - return crossing_edges; -} + /* Mark every edge that crosses between sections. */ -/* Emit a barrier into the footer of BB. */ + FOR_EACH_BB (bb) + FOR_EACH_EDGE (e, ei, bb->succs) + { + unsigned int flags = e->flags; + + /* We should never have EDGE_CROSSING set yet. */ + gcc_checking_assert ((flags & EDGE_CROSSING) == 0); + + if (e->src != ENTRY_BLOCK_PTR + && e->dest != EXIT_BLOCK_PTR + && BB_PARTITION (e->src) != BB_PARTITION (e->dest)) + { + VEC_safe_push (edge, heap, crossing_edges, e); + flags |= EDGE_CROSSING; + } -static void -emit_barrier_after_bb (basic_block bb) -{ - rtx barrier = emit_barrier_after (BB_END (bb)); - bb->il.rtl->footer = unlink_insn_chain (barrier, barrier); + /* Now that we've split eh edges as appropriate, allow landing pads + to be merged with the post-landing pads. */ + flags &= ~EDGE_PRESERVE; + + e->flags = flags; + } + + return crossing_edges; } /* If any destination of a crossing edge does not have a label, add label; @@ -2108,6 +2220,8 @@ partition_hot_cold_basic_blocks (void) if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1) return 0; + df_set_flags (DF_DEFER_INSN_RESCAN); + crossing_edges = find_rarely_executed_basic_blocks_and_crossing_edges (); if (crossing_edges == NULL) return 0; @@ -2139,6 +2253,38 @@ partition_hot_cold_basic_blocks (void) VEC_free (edge, heap, crossing_edges); + /* ??? FIXME: DF generates the bb info for a block immediately. + And by immediately, I mean *during* creation of the block. + + #0 df_bb_refs_collect + #1 in df_bb_refs_record + #2 in create_basic_block_structure + + Which means that the bb_has_eh_pred test in df_bb_refs_collect + will *always* fail, because no edges can have been added to the + block yet. Which of course means we don't add the right + artificial refs, which means we fail df_verify (much) later. + + Cleanest solution would seem to make DF_DEFER_INSN_RESCAN imply + that we also shouldn't grab data from the new blocks those new + insns are in either. In this way one can create the block, link + it up properly, and have everything Just Work later, when deferred + insns are processed. + + In the meantime, we have no other option but to throw away all + of the DF data and recompute it all. */ + if (cfun->eh->lp_array) + { + df_finish_pass (true); + df_scan_alloc (NULL); + df_scan_blocks (); + /* Not all post-landing pads use all of the EH_RETURN_DATA_REGNO + data. We blindly generated all of them when creating the new + landing pad. Delete those assignments we don't use. */ + df_set_flags (DF_LR_RUN_DCE); + df_analyze (); + } + return TODO_verify_flow | TODO_verify_rtl_sharing; } |